Stainless or factory exhaust manifolds, results inside.

[Boosted Zed]

Yes Sydneykid I was talking to Geoff from SSS Automotive about them manifolds on his Gibson engine a while back and sound the go. I guess not available though and were they extrude honed or exotic nicely made from the start?

I am a little confused though if Gibson? did it as in improved on factory to get more flow then there must be a need, or just more like I am saying it all helps and if can have less restriction and more even flow? It is sometimes hard to not focus on perfect when better or best available is a good option hey? As I take it taht the manifolds youare talking about arenot available?

I think we are on the same page though as I said as an example no point in having big throttle bodies on a zed without improving further down the line. But no point in going big turbo's and pumping more boost to get the power without improving flow out of head otherwise just adds heat and stress with out freeing up to get the full potential.

[lwells]

Hi SK,

Hmmm.. some food for thought there.

It is effective when the component being honed is the weak link in the chain, but it is waste of time and money when there are other components negating the benefits (because they are the weak link in the chain).

I take it then you don't see the bang-for-buck equation being favourable for a mild street cars (but perhaps if one already has an extensive array of modifications -- head porting, cams, turbos, etc)? What of the other associated benefits, rather than outright power: faster spool/better 'response', more (and more consistent) airflow?

It must be nice having your own fabricator I assume it would be hideously expensive to have such one-off items made?

Cheers,

Lucien.

[Beer Baron]

I fabricated something this morning before I had a shower. some people might call it shit.............and they'd be right. as a one off item it was quite expensive as it consisted of mostly imported beer and scotch fillet steak.

[DoughBoy]

I fabricated something this morning before I had a shower. some people might call it shit.............and they'd be right. as a one off item it was quite expensive as it consisted of mostly imported beer and scotch fillet steak.

How did it flow? Notice any MPH gains before it hit the end of the bend? Got any data from Japanese ones?

[Boosted Zed]

Beer Baron stop mixing V and Beer it makes you silly.

[dangerous_daveo]

Thanks for the answer. The reason I have been told to use steampipe is being thicker it holds in the heat better, you can design it to suit your application, and set it up so it pulses. Holding in the heat so I have been told is a good thing, as thiner(ie hotter) air travels faster, hence reducing lag, etc. Same deal with a turbo tea cossie thing, keeping the heat in, is the benifit. Or so I have been told.

Anyway. After thinking about it a bit more, more so on RB20/25s and the cast HKS etc manfiolds, whats the go with them? As I would be assuming they would be better than stock (?) so if you then did your honing on them, they would be better than a stock honed manifold correct?

Sorry for what might seem stupid questions, just no one else has asked them, and I feel them to be kinda valid.

[Cubes]

How did it flow? Notice any MPH gains before it hit the end of the bend? Got any data from Japanese ones?

Provided a decent weight reduction no doubt. Best I have achieved is 2kg.

[Talej]

Told the dog and the wife I would be coming to bed a bit later now.

All I want to know is which one to you snuggle up to at night, your wife or the dog?

[Boosted Zed]

Can't extrude hone stainless as it is too hard. We will have figures and a seperate thread for RB25 and you will be suprised also.

Yes dangerous_daveo well made manifolds out of steam pipe is the go especially if high temp HPC coated for GTS-T's and if going high mount turbo as they have more space and can have longer more even runners. For GTR much harder to improve on factory.

[dangerous_daveo]

Can't extrude hone stainless as it is too hard.   We will have figures and a seperate thread for RB25 and you will be suprised also.  

Yes dangerous_daveo well made manifolds out of steam pipe is the go especially if high temp HPC coated for GTS-T's and if going high mount turbo as they have more space and can have longer more even runners.  For GTR much harder to improve on factory.

Ahhh, now it makes more sence!

Still if you guys ever get the chance Id be interested, as I guess a few others in regards to the bolt on HKS etc cast items and doing the same processes with them, or are they stainless (I dont think they are...?)

[Cubes]

Ahhh, now it makes more sence!

Still if you guys ever get the chance Id be interested, as I guess a few others in regards to the bolt on HKS etc cast items and doing the same processes with them, or are they stainless (I dont think they are...?)

hehe you answered your own question.

[GTR32]

How did it flow? Notice any MPH gains before it hit the end of the bend? Got any data from Japanese ones?

heh heh just (don't want to know) what boost he was running. I'm not prepared to ask about dump pipes now...ever. Anyway you guys are *****s, can never forget army time when 5 days of rat packs accumulated and then a strong coffee would suddenly see figures grasping an M16 1m off the ground and travelling 150 knots with a roll of toilet paper (known as date roll) heading for the jungle...talk about boost...made the extrude hone photos look tame.

So John what about the offer from Scooby?????

[Wazz]

I might be keen to do a test on these and compir on a r32, rb26 in the silvia.. stock turbos, could do it with stock dumps and custom 3inch dumps aswell if i end up getting a tig,

tests would be done on stock boost(dont know wat it is yet.. as the engine isnt quite in the car yet lol

how ever i have to see how the car runs first as it has a mines ECU tuned for jap fuel

so i dont want it to go bang regardless

[Beer Baron]

Beer Baron stop mixing V and Beer it makes you silly.

yeah, I have been known to loose my composure. :alcoholic

BTW for those that care, yes the japanese ones have a slight flow advantage, but my aussie fabrication one is much larger.

[Beer Baron]

heh heh just (don't want to know) what boost he was running. I'm not prepared to ask about dump pipes now...ever. Anyway you guys are *****s, can never forget army time when 5 days of rat packs accumulated and then a strong coffee would suddenly see figures grasping an M16 1m off the ground and travelling 150 knots with a roll of toilet paper (known as date roll) heading for the jungle...talk about boost...made the extrude hone photos look tame.

So John what about the offer from Scooby?????

mmm the one man rat packs were ok. I remember the 8 man rat packs were dodgy though. no choco, no chewy. ripped off. plus those tins of 'lamb' and stuff were dodgy as.

[Scooby]

I know one bloke who's dog wouldn't eat the corned beef. Anyway I digress...

John are you up for the test I proposed or not??

Regards

[180bfj20det]

Plus stainless manifolds are more likely to crack,  

they do radiate much more heat

Nice thread but you are unfortunately wrong about stainless steel.

First of all, stainless steel, in comparison to either mild steel or cast iron (factory manifold material) has a much lower thermal conductivtiy constant (http://www.engineersedge.com/properties_of_metals.htm) meaning it WILL retain heat within the exhaust runner and manifold better than the mild or cast steels. Consequently, it does NOT "radiate much more heat" as you quoted and as such stainless steel is a much better option on thermal grounds as increased heat within the manifold maintains gases at their maximum velocity.

Secondly, you are right about stainless steel manifolds being more likely to crack, but this is more due to the competancy of the welder. Steam pipe can be bought in many stainless steel options but the most common are the 304 and 316 varieties which are 3.2mm thick (the one's I use) and given the right penetration and constant heat, will not crack and WILL always outlast mild steel counterparts.

Lastly, stainless steel, other than its thermal properties and durability, is a much more attractive material and stronger material per unit weight than either cast or mild steels.

In summary - Stainless steel:

1) Excellent heat retention (low thermal conductivity)

2) Durability

3) Strength per unit weight

4) Cosmetics

These four points are the reason why stainless steel is exploited by companies such as HKS and why only the best manifolds are made from stainless steel. What ever is made from cast or mild can be improved on in stainless.

My 2 cents

[Boosted Zed]

Interesting although I think the cast factory ones are much thicker and I guess why staino ones are lighter? Also I could be wrong but stainless manifolds seem to glow more than stock ones when on the dyno and if I had to touch one I would rather touch the cast factory one especially a coated one. Just an experienced opinion, science may prove different. But then this is side issue flow is the main deal, have you flow tested any or if you have some for GTR and they flow more we will sell them?

Scooby up for test YES, YES, YES, OK, OK, OK, I WILL, I WILL, I WILL, LUV TO, LUV TO, LUV TO.

[Turbine]

Hi John, this might sound like a strange question, but which way did they test the flow?  In the direction of the normal exhaust flow?  If so, how did they block off the 2 cylinders they weren't testing?  If they blocked off the 2 non testing cylinders at the cylinder head flange, then I am not surprised that the centre cylinder flow less.  The aerodynamics of the manifold would cause that.

The only real way to test flow equality it is with all three cylinders being used in the same time frame as the cylinder firing.  But that would be difficult as the primary runners are not the same length, hence the pulses would reach the secondary pipe at different intervals, ie; create interference.

Perhaps a better porting result would be achieved if the primaries were of equal volume, as this would give the same result as equal length.   That is where flow testing of equal length primary pipes, as you would find in any decent stainless steel pipe manifold, won't show up their true advantage.  Flow rate is not the only gain to be had from equal length primary pipes.

An example, the GTSR Group A exhaust manifold barely flows any more than the standard RB20DET exhaust manifold, but they make 25 rwkw extra.  Why?  Because of the extractor effect of the equal length primary pipes.

Hi Sydney Kid. What length would they be set at? This interests me because i wish to make up a custom manifold for my RB20, and because I have no room issues under my bonnet i can basically plumb the exhaust straight out of the head, into the turbo and straight out the side of the car.

Engine is redlined at 8500RPM and spends all of it's time between 5000 and 8250RPM.

Cheers

Turbine

[GTRgeoff]

heh heh just (don't want to know) what boost he was running. I'm not prepared to ask about dump pipes now...ever. Anyway you guys are *****s, can never forget army time when 5 days of rat packs accumulated and then a strong coffee would suddenly see figures grasping an M16 1m off the ground and travelling 150 knots with a roll of toilet paper (known as date roll) heading for the jungle...talk about boost...made the extrude hone photos look tame.

mmm the one man rat packs were ok. I remember the 8 man rat packs were dodgy though. no choco, no chewy. ripped off. plus those tins of 'lamb' and stuff were dodgy as.

I know one bloke who's dog wouldn't eat the corned beef. Anyway I digress...

Geez, a thread full of AJ's (or ex's) and a dodgy ex-copper No wonder the topic has turned to crap.

180: I don't disagree with you on those conclusions, and just for those who want the conversion the SS comes in at about 14W/m.degC compared to the carbon steel with a best of 36, so less than half of the conductivity. As well the stainless would be expected, as a polished product, to exhibit lower radiative properties, except that it becomes hot and glows into the light emitting spectrum, completely negating the polished finish. My view is, regardless, both products need to be coated or wrapped to retain thermal energy so neither is a better option.

To achieve the best result from stainless, for flow and heat retention purposes equivalent to the UAS manifolds, a significant fabrication expense would be incurred, which I guess is the fundamental issue, We can get the factory product and improve it, or spend a truck load of cash. The decision makes itself.